When it comes to controlling the many non-native, invasive plants in northern Arizona, weed warriors call on every tactic in the book. As they seek to minimize the spread of a weed called diffuse knapweed, they’re turning to a tiny ally: a weevil that loves to eat knapweed seeds.

Diffuse knapweed is a low-growing shrub that originated on the Russian steppes. Since the 1980's, it’s taken over roadsides and pastures in the region. It’s a heavy seed producer and a tough competitor against native plants.